How do we determine the circumference of the sun and the distance of the sun from the earth?
Kepler constructed a scale model of the solar system – so we knew the relative distances to the planets and the sun.The absolute distance to the sun was measured using this and using parallax measurements to get the distances to planets. We can see the sun and measure its angular size – i.e. what angle do you turn your head through to move from looking at the bottom to looking at the top). If twe have the distance to the sun and its angular size, we just solve a triangle to get the sun’s absolute size (diameter in km). circumference is pi x diameter!
